Note: Descriptions are shown in the official language in which they were submitted.
21058 1 0
ELECTRICAL CONNECTOR
Background of the Invention
This invention relates to electrical connectors, and, more particularly, to
separable
electrical connectors suited for use under high-voltage conditions. Still more
particularly, this
invention relates to gas actuated high-voltage bushings having a contact
mounted within a bore
for recipra;,al movement within a bushing housing.
High-voltage separable conpexrtors innerconnect sources of energy such as
transformers
to distribution networks or the like. The situations typically encountered in
the connection and
disconnection of electrical crn~ne~tors and power distributions include
"loadmake", "loadbreak",
;md "fault closure". Loadmake includes the joinder of male and female contact
elements, one
energized and the other engaged with a normal load. An arc of moderate
intensity is struck
hetween the contact elements as they approach one another and until joinder.
Loadbreak
includes the separation of such mated male and female contact elements, while
they supply
power to a normal load. Ma3erate intensity arcing again occurs between the
contact elements
fiom the point of separation tJnereof until they are somewhat removed from one
another. Fault
closure includes the joinder of male and female contact elements, one
energized and the other
engaged with a load having a fault, e.g., a short circuit condition. A
substantial arcing occurs
between the contact elements as they approach one another and until joinder,
giving rise to the
possibility of explosion and acxompanying hazard to operating personnel.
The prior art teaches the use of materials which emit arc-quenching gas when
subjected
to arcing, thus adequately dissipating the moderate intensity of arcs which
occur during
loadmake and loadbreak. Thc: problem situation is fault closure, in which
considerably more
wc-quenching gas and mechanical assistance are required to extinguish the arc.
During fault
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210581 0
closure, the gas generated pressures may be fifty times greater than such
pressures during
loadmake. With respect to fault closure, the prior art has relied upon the use
of the arc-
quenching gas to assist in accelerating the contact elements into engagement,
thus minimizing
arcing time.
A typical prior art electrical connector includes a bushing well connected to
the
transformer, a bushing insert which contains a female contact assembly
connected to the well,
;and an elbow connected to a~ distribution line and containing a male contact
to join an insert
:female contact in the female contact assembly. Because closure of the male
and female contacts
cyan occur under activated conditions or under fault conditions, the female
contact is arranged
to move within the insert to hasten the closure of the male and female
contacts and thus
extinguish any arc created. However, it is necessary to maintain electrical
continuity during the
travel of the female contact assembly. The connection between such female
contact assembly
and the remainder of the bushing insert must be flexible so as not to impede
its movement but
sufficient to carry the high currents in the circuit. Typical prior art
devices include a female
contact which has a piston that is moveable between a first and second
position. Gas pressure
vrhich is generated by arcing during fault closure accelerates the female
contact toward the male
contact, thus hastening contract engagement and decreasing the time duration
of the arc.
ll~echanisms for achieving these results have not always produced sufficient
current paths causing
the connectors to run hot, and interfering with proper operation of the
distribution network and
in the extreme, leading to the destruction of the bushing inserts.
~~UMMARY OF THE INVENTION
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210581 0
69469-138
The pre~;ent invention includes a female electrical
connector comprising a conductive housing having a first end
adapted to receive a male contact element, a second end adapted to
be closed, and an internal wall surface providing an axially
extending opening therebetween. The connector includes an
elongate female contact assembly including a tubular conductive
piston mounted on a holder within and in conductive relationship
with the housing and axially moveable between a normal or first
position wherein the piston is maximally spaced from the first
housing end and a second position. The piston provides a chamber
adjacent the second housing end. The assembly also includes
female contact means for engaging the male contact element carried
by and moveable with and in electrically conductive relationship
with the piston. The female contact assembly is configured to
transmit to the chamber arc-quenching gas which is generated when
an arc is struck between the male contact element and the female
contact means. The predetermined value of gas pressure is
associated only with fault closure so that the piston is retained
by the mechanism in the first position except during fault
closure.
The female contact assembly includes frictional and
mechanical inhibitors for retaining the piston in the first
position until gas pressure in the chamber attains a predetermined
value and for releasing the piston to cause the same to move
toward the second position when said pressure exceeds said
predetermined value. The inhibitors include a knurled surface on
the piston which engages the holder of the piston; dimples in the
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21 058 1 0
69469-138
holder crimping the holder gainst the knurled surface; stakes on
the holder coined into the surface of the piston; and stops on the
holder for engaging a stop shoulder on the piston.
More generally, the present invention provides a
connector for connecting or disconnecting an energized high
voltage circuit by engagement or disengagement with another
connector having a contact member, comprising: a sleeve having an
axial passage therethrough with an electrically conductive
surface; a contact. element disposed within said passage for
engaging the contact member; guide means attached to one end of
said contact element for guiding the contact member toward said
contact element and for evolving an arc-quenching gas in response
to an arc being struck between the contact member and said contact
element; said contact element including piston means responsive to
such evolved gas for jointly displacing within said passage said
guide means and said contact element toward the contact member;
support means fixedly secured within said sleeve for reciprocably
supporting said piston means within said passage of said sleeve;
and inhibitor means associated with said support means and piston
means for inhibiting the movement of said piston means within said
sleeve until a predetermined pressure is achieved by the arc-
quenching gas and for electrically connecting said piston means
with said conductive surface for providing electrical continuity
therebetween.
Other objects and advantages of the present invention
will appear from the following description.
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21 058 1 0
BRIE:E DESCRIPTION OF THE DRAWINGS
For a detailed description of a preferred embodiment of the invention,
reference will now
Eye made to the accompanying; drawings wherein:
Figure 1 is a longitudinal cross-section view of a male electrical contact
connector to be
inserted into a female electrical contact connector;
Figure 2 is an e~larg;ed cross-sectional side . elevatio~nal view of the
female contact
connector shown in Figure 1;
Figure 3 is an enlarged cross-sectional side elevational view of the female
contact
assembly of the connector shown in Figure 2;
Figure 4 is an enlarged cross-sectional view at plane 4-4 of Figure 6
illustrating stops;
Figure 5 is an enlarged view of a portion of Figure 6 illustrating stops;
Figure 6 is a cross-se<;tional side elevational view of the female contact
connector of
Figure 2 in the outward, expanded position;
Figure 7 illustrates an ;alternative embodiment of the stops shown in Figure
5;
Figure 8 is a cross-sectional side elevational view of an alternative
embodiment of the
female contact connector shown in Figures 1-7;
Figure 9 is an end vievv of the alternative female contact connector shown in
Figure 8;
Figure 10 is a cross-se<;tional side elevational view of an alternative
embodiment of the
female contact connector of the present invention;
Figure 11 is a cross-sectional side elevational view of the female contact
connector shown
in Figure 10 in the outward, expanded position;
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21 058 1 0
Figure 12 is a cross-~~ectional, side elevational view of another alternative
embodiment
of the female contact connector of the present invention;
Figure 13 is a cross-s,~tional, side elevational view of the female electrical
connector of
Figure 12 shown in the outward, expanded position;
Figure 14 is a cro:~s-sextional, side elevationah view of still another
alternative
embodiment of the female eo~ntact connector of the present invention;
Figure 15 is a cross-sectional, side elevational view of the female contact
connector
~~hown in Figure 14 with the connector in its outward, expanded position;
Figure 16 is a cross-sr~tional, side elevational view of still another
embodiment of the
female contact connector of tJhe present invention;
Figure 17 is a cross-sExtional, side elevational view of the female contact
connector of
Figure 16 shown in the outw~~rd, expanded position;
Figure 18 is a cross-sectional, side elevational view of the female contact
connector
shown in Figures 16 and 17 having a molded rubber casing;
Figure 19 is a cross-sectional, side elevational view of still another
embodiment of the
fE:male contact connector of tree present invention;
Figure 20 is a cross-sectional, side elevational view of the female contact
assembly shown
in Figure 19 in the outward, expanded position;
Figure 21 is an exploded view of the arc snuffer housing to be assembled
within the
conductive sleeve of the female contact connector shown in Figures 19 and 20;
Figure 22 is a cross-sectional view of the arc snuffer housing disposed within
the
conductive sleeve shown in Figures 19 and 20; and
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21 058 1 0
Figure 23 is an end view of the assembly shown in Figure 22;
Figure 24 is an enlarged cross-sectional side elevational view of the
preferred
embodiment of the female contact assembly of the present invention;
Figure 25 is an enlarged cross-sectional view of detail "A" shown in Figure
24;
Figure 26 is a sectional view taken at plane 26-26 of Figure 25; and
Figure 27 is a sectional view at plane 27-27 shown in Figure 25.
DESCRIPTION OF A PREF F EMBODIMENT
Referring initially to Figure 1, the electrical connector 10 of the present
invention
includes a female contact connector 20, as for example a bushing insert or
connector, connected
to a portion of a high-voltage circuit (not shown), and a male contact
connector 30, such as an
elbow connector, electrically connected to another portion of the high-voltage
circuit. As
shown, the male contact connector 30 is in the form of a cable termination
device, such as an
elbow. Male and female conl:act connectors 30, 20, respectively interfit to
achieve electrical
connection.
The male connector 30 includes an elastomeric housing 32 of a material such as
EPDM
(ethylene-propylene-dienemonomer) rubber which is provided on its outer
surface with a
ccmductive shield layer 34 which is grounded (not shown). One end of a male
contact element
or probe 40, of a material such as copper, extends from a conductor contact 36
within housing
30 into a cup shaped recess 38 of housing 32. At the opposite end of the male
contact element
40 extends an arc follower 42 of ablative material. A preferred ablative
material for arc
follower 42 is acetal co-polyrner resin loaded with finely divided melamine.
The ablative
m~iterial is typically injexrtion molded on an epoxy bonded glass fiber
reinforcing pin 44. A
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2105810
r~~;ess 46 is provided at the junction between metal rod 40 and arc follower
42. An aperture 52
i~~ provided through the exposed end of rod 40 for the purpose of assembly.
Referring now to Figures 1-7 illustrating the female connector 20, female
contact
connector 20 is a bushing insert composed of a shield assembly having an
elongated body
including an iruler rigid, metalllic, electrically conductive sleeve 50,
sometimes referred to as a
shield tube, having a non-conductive nose piece 52 secured to one end of
sleeve 50 by latching
means 54, and a casing 56 of elastomeric insulating material such as rubber,
synthetic rubber,
plastic or the like surrounding ,and bonded to the outer surface of sleeve 50
and a portion of nose
piece 52. A radially outer portion 58 of conductive elastomeric materizl is
bonded to the mid-
portion 55 of casing 56, all well known in the art. Bushing insert 20 is
electrically and
mechanically mounted to a bushing well (not shown) disposed on the enclosure
of a transformer
or other electrical equipment. For purposes of description, the term "inner"
shall mean the
direction toward the bushing well of the electrical equipment and the term
"outer" shall mean
the direction toward the nose piece 52 and male connector 30.
Conductive sleeve 50 is generally cylindrical having a central passageway 60
therethrough. Sleeve 50 has an inner end 62 which has a reduced inner diameter
63 which is
open to recess 64 formed by casing 56 which receives a portion of the bushing
well (not shown).
The open outer end 66 of conductive sleeve 50 includes an enlarged outer
diameter 67 with a
radially inwardly directed annular latching shoulder 69 forming an annular
latching groove 71.
Latching shoulder 69 and latching groove 71 form a part of latching means 54.
Nose piece 52 has an external circumferential groove 68 which serves as a
securing
deaente for complimentary ribbed portion 33 associated with elastomeric
housing 32 of male
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21 058 1 0
contact connector 30. The inner end 53 of nose piece 52 has a reduced outer
diameter wi:h a
ridially, outwardly projecting annular shoulder 55 for abutting the outer
terminal end 66 of
conductive sleeve 50. Inner end 53 includes a radially, outwardly directed
annular shoulder 57
adapted for being received b;y latching groove 71 and an outwardly facing
annular latching
groove 59 adapted for receiving annular latching shoulder 6~.wA~ular shoulder
59 and latching
groove 59 form the remainder of latching means 54.
Referring now particularly to Figures 2 and 3, the ferrfale contact cormector
20 further
includes a contact assembly 70. Contact assembly 70 includes a contact holder
80, a female
contact 90, a tubular arc snuffer housing 100, and an arc-quenching, gas-
generating arc snuffer
110. As best shown in Figure 2, the contact assembly 70 is disposed within
internal passageway
6~J of conductive sleeve 50. Contact holder 80 is generally cylindrical and
has a substantially
closed inner end 82 which is disposed within reduced diameter inner end 62 of
conductive sleeve
50. The external shape of contact holder 80 conforms to the generally
cylindrical shape of the
internal wall 51 of conductive sleeve 50. The inner end of contact holder 80
is knurled at 83
and then press fitted into reduced diameter 63 of inner end 62 of conductive
sleeve 50. A
cooperating snap ring and groove may be used to maintain inner end 82 within
end 62 of sleeve
51).
The inner rigid, metallic, electrically conductive sleeve 50 acts as an equal
potential
shield around the contact assernbly 70 disposed within internal passageway 60
of sleeve 50. A
sleeve made of a nonconductive material would not provide such a shield. It is
preferred that
sleeve 50 be made of an electrically conductive material so as to act as an
equal potential shield
and prevent any stress of the air within the sleeve SO and prevent any air
gaps around the contact
8
2105810
assembly 70. It is desirable to prevent any breakdown of the air within the
connector housing
during normal assembled operation.
A threaded aperture 84 extends longitudinally through closed inner end 82
along the
central axis 85 of sleeve 50. To permit the female contact connector 20 to be
electrically and
mechanically coupled to a bushing well (not shown), a hex slot 86 is provided
in inner end 82
to receive a hexrod extending; through contact assembly 70 for the turning of
female contact
connector 20 to threadingly engage a stud (not shown) extending from the
bushing well mounted
on the electrical equipment.
The cylindrical portion of contact holder 80 forms a cylinder or bore 88 sized
for
rexeiving one end of female contact 90. Female contact 90 is generally
cylindrical and includes
a piston or barrel 92 having a ~alurality of projecting contact fingers 94
extending from its outer
end. Contact fingers 94 are formed by providing a plurality of slots 96
azimuthally spaced
around the outer end of female contact 90. Contact fingers 94 are shown in the
contracted
position in Figure 3 and are moved to an expanded position upon the insertion
of probe 40 as
hereinafter described with respect to Figure 4.
The inner end 91 of fern~le contact 90 is knurled at 98 around its outer
circumferential
surface to provide a frictional, biting engagement with the cylindrical wall
89 of contact holder
80~. This knurled interface 98 provides substantial friction and thus drag
between female contact
90 and contact holder 80. Tt~e knurled surface 98 not only ensures good
electrical contact
between holder 80 and contact 90, but also inhibits the reciprocation of the
piston or barrel 92
of contact 90 within the cylinder or bore 88 of holder 80 until such friction
is overcome by gas
pressure forces as hereinafter described. To provide additional resistance to
the movement of
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21 058 1 0
contact 90 within holder 80, a plurality of stakes or dimples 93, such as
three, may be made in
the cylinder wall 89 and into barrel 92 at knurled surface 98.
Referring now to Figures 3-6, the barrel 92 of female contact 90 further
includes an
annular counterbore 102 around its mid-portion forming an outwardly facing
annular shoulder
106. As best shown in Figure; 5, upon the assembly of female contact 90 within
the bore 88 of
contact holder 80; lanced stops 104 are formed by crimping a plurality of
inwardly directed tabs
formed in the cylindrical wall. 89 of holder 80 so as to project radially
inward such that stops
104 are received within counterbore 102. Lanced stops 104 preferably include
two
circumferential rows of four stops each approximately 90° apart. The
outer row of stops 104a
i:~ staggered with the inner row of stops 104 so as to be 45 ° apart.
Stops 104 are provided to
engage annular stop shoulder 106 of counterbore 102 upon the outward movement
of female
a~ntact 90 away from inner closed end 82 of holder 80 as shown in Figure 6.
Further, vent
hales 105, preferably two in number, are provided through the wall of
counterbore 102 adjacent
iks outer end.
Referring now to Figure 7, stops 104 may alternatively be formed by providing
an
annular indentation 107 which is mechanically formed by rollers passing around
the external
surface of cylindrical wall 89 of contact holder 80. The protrusion of lanced
stops 104 or
armular indentations 107 and their projection into bore 88 may be varied to
adjust the contact
of stops 104 or indentation 107 against the annular bottom surface of
counterbore 102. This
adjustment may be used to vary the frictional and mechanical engagement
between barrel 92 and
the bore 88 of holder 80 to thereby assist in changing the force required to
move female contact
9C~ within contact holder 80.
2105810
Referring again to Figure 3, arc snuffer 110 is generally cylindrical and
includes two
annular grooves 116, 117. The inner end 119 has an enlarged diameter with the
diameter
change forming an inwardly facing frusto-conical shoulder 121. The enlarged
diameter on the
inner end 119 of arc snuffer 100 provides additional volume within bore 88 for
the pressure
generated by the arc-quenching gas. Arc snuffer housing 100 is made of plastic
and is molded
around arc snuffer 110. Out,~r terminal end 108 of arc snuffer housing 104
includes a plurality
of guides 112, preferably four in number, azimuthally spaced around end 108.
Guides 112 form
an inwardly directed annular stop shoulder 114 and an outwardly facing
inwardly tapering guide
surface 115 to guide probe 40 into contact assembly 70. During the molding
process, annular
;grooves 116, 117 receive molded plastic which form annular ribs received
within grooves 116,
117 to lock arc snuffer 110 within housing 100.
The inner end 118 of housing 100 is adapted to receive the projecting contact
fingers 94
of female contact 90. Housing 100 includes threads 119 along a portion of
inner end 118 for
threaded engagement with external threads on female contact 90. Alternatively,
inner end 119
may be heated by induction heat with the plastic of inner end 118 melting
around preferably a
knurled surface of female contact 90 to attach the arc snuffer assembly to
female contact 90.
l~n securing the arc snuffer assembly to female contact 90, the arc snuffer
assembly and female
<;ontact 90 move as a unit wivthin conductive sleeve 50 and contact holder 80.
One of the advantages of the present invention is that the casing 56 may be
molded to
the exterior of nose piece 52 and conductive sleeve 50 without having contact
assembly 70, or
a portion thereof, previously installed within conductive sleeve S0. One
disadvantage of the
Frrior art is the molding of t7le housing after one or more parts of the
contact assembly has
11
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21 058 1 0
already been installed such that the heat from the molding process adversely
affects the
components housed within the sleeve.
Prior to the assembly of contact assembly 70 within aperture 60 of conductive
sleeve 50,
.a foam tape 109 is wrapped around the inner end 118 of arc snuffer housing
100. Upon the
;3ssembiy of contact assembly 70 within conductive sleeve 50, foam tape 109 is
contracted into
:pealing engagement between the adjacent surfaces of housing 100 and
conductive sleeve 50 to
prevent the passage of the are-quenching gas generated during a switching
operation between
contact assembly 70 and conductive sleeve 50. Thus, the pressure of the arc-
quenching gas is
al directed against the contact assembly 70 to move assembly 70 into the
outward extended
position shown in Figure 6 during a fault condition.
Referring now to Figures 2 and 6, Figure 2 illustrates the female contact
connector 20
in the normal, contracted operating position. Figure 6 illustrates the female
contact connector
2.0 in the fault, outward or expanded position. During a loadbreak or
switching operation, the
rnale contact connector 30, i.e. elbow and probe assembly, is separated from
the female contact
connector 20, i.e. bushing insert. During the loadbreak, separation electrical
contact occurs
between the probe 40 and female contact 90. During this separation as probe 40
is pulled
outward from female connector 20, there is a mechanical drag between the probe
40 and contact
fingers 94 of female contact 5~0. This drag might otherwise result in the
movement of female
contact 90 within contact holder 80, but is prevented from doing so due to the
frictional forces
at the innerface between knurled surface 98 and the inner circumferential
surface of cylindrical
wall 89 of contact holder 80 and due to dimples 93 in holder 80 crimping wall
89 against
knurled surface 98.
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21058 1 0
In the joinder of male connector 30 and female connector 20 during loadmake,
one
connector is energized and the other is engaged with a normal load. Upon the
attempted closure
of male contact probe 40 with female contact 90, an arc is struck prior to
actual engagement of
probe 40 with contact fingers 94 and continues until solid electrical contact
is made. The arc
passes from male contact probe 40 to arc snuffer 110 and passes along the
inner circumferential
surface 111 of arc snuffer 1;l0 thereby causing the generation of arc-
quenching gases. These
gases are directed inwardly Writhin the bore 91 of female contact 90 and the
bore 88 of contact
holder 80. The pressure of these gases applies a force to inwardly facing
shoulder 121 of arc
snuffer housing 100 and to the; inner terminal end 122 of female contact 90.
An arc of moderate
intensity will not produce adequate gas pressure to apply sufficient force on
the end 124 of arc
snuffer housing 100, inner end 119 of arc snuffer 110, and terminal end 122 of
female contact
S~0 to overcome the frictional engagement of cylindrical wall 89 and dimples
93 with knurled
surface 98.
However, during fault closure, one of the connectors 20, 30 is energized and
the other
is engaged with a load having a fault, e.g. a short circuit condition. Under
such circumstances,
a substantial arcing occurs between male contact probe 40 and female contact
90 as probe 40
a~aproaches opening 126 in ;irc snuffer 110. In fault closure, arc snuffer 110
generates
substantial arc-quenching gasea which produce a gas pressure within bore 88
that is sufficient
to act upon shoulder 121 of the: arc snuffer assembly and the terminal end 122
of female contact
9i) and overcome the frictional engagement of knurled surface 98 with inner
wall 89 and dimples
9:3. This arc-quenching gas pressure moves the entire contact assembly 70,
i.e. arc snuffer
housing 100, arc snuffer 110, a,nd female contact 90, toward probe 40 to more
quickly establish
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electrical contact between male contact probe 40 and female contact fingers
94. This accelerated
electrical connection reduces the fractional time required to make connection
and thus reduces
the possibility of explosion and any accompanying hazard to operating
personnel during a fault
closure situation.
Referring now to Figures 24-26, there is shown the preferred embodiment of the
female
~;ontact assembly of the female contact connector of the present invention.
The female contact
nonnector 500 includes a cornductive sleeve, non-conductive nose piece, and a
easing which are
substantially the same as treat of sleeve 50, nose piece 52, and casing 56
shown in the
Embodiment of Figure 2. The female contact connector 500, however, includes a
preferred
<;ontact assembly 570. Contract assembly 570 includes a contact holder 580, a
female contact
_'i90, a tubular arc snuffer housing 600, and an arc-quenching, gas-generating
arc snuffer 610.
",Che contact assembly 570 is disposed within the internal passageway of a
conductive sleeve,
substantially the same as that of sleeve 50 of Figure 2. Contact holder 580 is
generally
cylindrical and has a substanl:ially closed inner end 580 which is disposed
within the reduced
diameter inner end of the conductive sleeve. The external shape of contact
holder 580 conforms
t~~ the generally cylindrical shape of the internal wall of the conductive
sleeve. The inner end
o~f contact holder 580 is knurled at 583 and then press fitted into the
reduced diameter of the
inner end of the conductive sleeve. A cooperating snap ring and groove may be
used to
maintain inner end 582 within the inner end of the conductive sleeve.
A threaded aperture 584 extends longitudinally through closed inner end 582
along the
a~ntral axis 585 of the conductive sleeve. To permit the female contact
connector to be
electrically and mechanically coupled to a bushing well (now shown), a hex
slot 586 is provided
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210581 0
in inner end 582 to receive <i hex rod extending through contact assembly 570
for the turning
of the female contact connecaor to threadingly engage a stud (not shown)
extending from the
bushing well mounted on the electrical equipment.
Arc snuffer 610 is generally cylindrical and includes an outwardly projecting
annular rib
616. The inner end 619 has an enlarged diameter with the diameter change
forming an inwardly
facing frusto-conieal shoulde~.~ 621. The enlarged diameter on the inner end
619 of arc snuffer
X500 provides additional volume within bore 588 for the pressure generated by
the arc-quenching
~;as. Arc snuffer 600 is made: of plastic and is molded around arc snuffer
610. Outer terittinal
c;nd 608 of arc snuffer housing 600 includes a plurality of guides 612
azimuthally spaced around
a;nd 608. Guides 612 form an inwardly directed stop shoulder 614 in an
outwardly facing
inwardly tapering guide surface 615 to guide probe 40 into contact assembly
570. During the
rnolding process, annular rib 616 is surrounded by molded plastic which forms
an annular
~;roove 617 to lock arc snuffer 610 within housing 600. Arc snuffer 610 also
includes an
inwardly tapering conical surface 618.
As described with respect to Figure 1-7, a foam tape 609 is wrapped around the
inner
end 618 of arc snuffer housing; 600 to provide sealing engagement between the
adjacent surfaces
of housing 600 and the outer conductive sleeve to prevent the passage of arc-
quenching gas
generated during a switching operation between contact assembly 570 and the
conductive sleeve.
Thus, the pressure of the arc-quenching gas is all directed against contact
assembly 570 to move
assembly 570 into the outward extended position during a fault condition.
The cylindrical portion of contact holder 580 forms a cylinder or bore 588
sized for
rcxeiving one end of female contact 590. Female contact 590 is generally
cylindrical and
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210581 0
includes a piston or barrel 592 having a plurality of projecting contact
fingers 594 extending
from its outer end. Contact fingers 594 are formed by providing a plurality of
slots .596
;3zimuthally spaced around the outer end of female contact 590. Contact
fingers 594 are shown
in the contracted position in Figure 24 and are moved to an expanded position
upon the insertion
~~f probe 40 as previously de;scribed. -
The inner end 591 of female contact 590 is knurled at 598 around its outer
circumferential surface to provide a frictional, biting engagement with the
cylindrical wall 589
of contact holder 580. A plurality of dimples 593, preferably two which are
180° apart, are
made in the outer surface of cylindrical wall 589 and projecting into the
knurled surface 598 of
barrel 592. Dimples 593 have a 60° included angle. The knurled surface
598 and dimples 593
provide substantial friction and thus drag between female contact 590 and
contact holder 580.
'Che knurled surface 598 and dimples 593 not only ensure good electrical
contact between holder
_'i80 and contact 590, but also inhibit the reciprocation of the piston or
barrel 592 of contact 590
within the cylinder or bore 588 of holder 580 until such friction is overcome
by gas pressure
forces as hereinafter described.
Referring now to Figure 24-27, the barrel 592 of female contact 590 further
includes an
annular counterbore 602 around its mid-portion forming an outwardly facing
annular shoulder
fi06. Upon the assembly of female contact 590 within the bore 588 of contact
holder 580,
lanced stops 604 are formed by crimping a plurality of inwardly directed tabs
formed in the
cylindrical wall 589 of holder 580 so as to project radially inward such that
stops 604 are
received within counterbore 642. Lanced stops 604 preferably include eight
inwardly directed
tabs azimuthally spaced in a row around the outer circumference of cylindrical
wall 589 of
16
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210581 0 .
holder 580. The outer row o~f stops 604A is staggered with the inner row of
stops 604 so as to
be 45 ° apart. Stops 604 are provided to engage annular stop shoulder
606 of counterbore 602
upon the outward movement of female contact 590 away from inner closed end 582
of shoulder
580.
The protrusion of lanced stops 604 and their projection into counterbore 602
may be
varied to adjust the contact of stops 604 against the annular bottom surface
603 formed by
.counterbore 602. This adjustment may be used to vary the frictional and
mechanical engagement
'between barrel 592 and holler 580 to thereby assist in changing the force
required to move
female contact 590 within contact holder 580. Further, vent holes may be
provided through the
wall of counterbore 602 adjacent its outer end.
A plurality of wedges or stakes 620 are formed in the cylindrical wall 589 of
contact
lholder 580. There are preferaibly six stakes disposed azimuthally around the
outer circumference
of cylindrical wall 589. StakEa 620 are longitudinal indentations in
cylindrical wall 589 with the
1'~ongitudinal axis of stake 620 being parallel to axis 585. Upon the
formation of stake 620, a
cramp or inclined surface 6:'.2 is formed facing annular stop shoulder 606 on
barrel 592.
.Although stakes 620 appear to be in alignment with stops 604, such alignment
is shown for
illustration purposes only since stakes 620 may or may not be in alignment. In
the preferred
embodiment, the six stakes 620 are not in alignment with the eight stops 604.
As best shown
i.n Figure 27, the formation of stakes 620 cause stakes 620 to become coined
into the bottom
surface 603 of counterbore 602. Thus, stakes 620 provide a further frictional
and mechanical
engagement between contact '.i90 and contact holder 580 to inhibit the
reciprocation of the piston
or barrel 592 of contact 590 within the cylinder or bore 588 of contact holder
580 until such
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210581 0
frictional and mechanical engagement is overcome by gas pressure forces as
hereinafter
described.
Figure 24 illustrates the female contact assembly 570 in the normal,
contracted operating
position. During a loadbreak .or switching operation, the male contact
connector 30, i.e. elbow
aJld probe assembly, is separated from the female contact connector, i.e.
bushing insert. During
ttie loadbreak, separation electrical contact occurs between the probe 40 and
female contact 590.
Daring the separation as probe 40 is pulled outward from female contact
assembly 570, there
is a mechanical drag between tt~e probe 40 and contact fingers 594 of female
contact assembly
5'70. This drag might otherwise result in the movement of female contact 590
within contact
holder 580, but is prevented from doing so due to inhibitor means including
the frictional forces
bf;tween the knurled surface :598 and the inner circumferential of cylindrical
wall 589; the
contact of dimples 593 in holder 580 crimping wall 589 against knurled surface
598; the contact
between stops 604 and surface 603 of barrel 592; and the coining of stakes 620
into surface 603
of barrel 592.
In the joinder of male connector 30 and female contact assembly 570 during
loadmake,
one connector is energized and the other is engaged with a normal load. Upon
the attempted
clnsure of male contact probe: 40 with female contact 590, an arc is struck
prior to actual
engagement of probe 40 with <;ontact fingers 594 and continues until solid
electrical contact is
made. The arc passes from male contact probe 40 to arc snuffer 610 and passes
along the inner
circumferential surface 611 of arc snuffer 610 thereby causing the generation
of arc-quenching
gases. These gases are directed. inwardly within the bore 591 of female
contact 590 and the bore
588 of contact holder 580. 'Ifie pressure of these gases applies a force to
inwardly facing
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210581 0
shoulde.- 621 of arc snuffer housing 6Cb and to the inner terminal end 622 of
female contact 590.
An arc of moderate intensity vvill not produce adequate gas pressure to apply
sufficient force on
die end 624 of arc snuffer housing 600, inner end 619 of arc snuffer 610 and
terminal end 622
of female contact 590 t~ overcome the inhibitor means.
However, during fault closure, either the male or female-connectof is
energized and the
other is engaged with a load having a fault, e.g. a short circuit condition.
Under such
circumstances, a substantial arching occurs between male contact probe 40 and
female contact
5!X0 as probe 40 approaches opening 626 in arc snuffer 610. In fault closure,
arc snuffer 610
g~:nerates substantial arc-quenching gases which produce a gas pressure within
bore 588 that is
sufficient to act upon shoulder 621 of the arc snuffer assembly in the
terminal end 622 of female
contact 590 and overcome the: frictional and mechanical engagement of the
inhibitor means.
Upon overcoming the inhibitor means, the arc-quenching gas pressure moves the
entire contact
assembly 570, i.e. arc snuffer housing 600, arc snuffer 610, and female
contact 590, toward
probe 40 to more quickly establish electrical contact between male contact
probe 40 and female
contact fingers 594. As the barrel 592 of female contact 590 moves outwardly
towards probe
40, stop shoulder 606 first engages the stakes 620 and in particular engages
the inclined surface
622 of stakes 620. The enlarged diameter knurled end 598 of barrel 592 is
inhibited as it
wc~ges and attempts to pass through cylindrical bore 588 beneath stakes 620.
Should the gas
pmssures produced by the arc snuffer 610 be sufficiently large to pass knurled
surface 598
beneath stakes 620, annular stop surface 606 will then engage stops 604 to
prevent further
movement of the female contact 590 within contact holder 580. The stakes 620
and stops 604
provide sufficient stop barriers to the movement of female contact 590 to
prevent knurled surface
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21058 1 0
598 from passing completely through cylindrical bore 588 of contact holder
580. The
accelerated electrical connection reduces the fractional time required to make
connection and
thus reduces the possibility of explosion and any accompanying hazard to
operating personnel
during a fault closure situation.
Referring now to Figures 8 and 9, there is illustrated various alternative
constructions
of the female contact connector shown in Figures 1-7. Arc snuffer housing 101
has been molded
around arc snuffer 110 such that arc snuffer 110 is disposed between an
annular outer shoulder
114 and an annular inner tang 222. Arc snuffer housing 101 is also shown
molded arouru an
outer knurled surface 99 of female contact 90. Annular stops 104 are shown
being received
within longitudinal slots 105 in barrel 92 of contact 90. The inner end 51 of
sleeve 50 is also
shown interferringly fit around the inner end 81 of contact holder 80. Contact
holder 80 is held
in position by a snap ring 83 rexxive~ within a groove 85 around the terminal
end 87 of holder
80. It should be apprexiated that one skilled in the art may make other
modifications to the
embodiment shown in Figures 1-7 without departing from the spirit of the
invention.
Figures 10-20 illustrate alternative embodiments of the female contact
connector 20 of
thf~. present invention. In the de:~cription which follows of the alternative
embodiments, like parts
to the preferred embodiment are: marked throughout the specification and
drawings with the same
reference numerals, respextivel;y. The drawings are not necessarily to scale
and certain features
and certain views of the drawings may be shown exaggerated in scale or in
schematic form in
the; interest of clarity and conciseness.
Referring now to Figures 10 and 11, a first alternative embodiment of the
female contact
connector of the present invention is shown. The first alternative female
contact connector 130
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210581 0
includes a conductive sleeve 1:32 having a non-conductive nose piece 134
secured to one end of
sleeve 132 by latch means 54, and a casing 56 bonded to the outer surface of
sleeve 132 and a
portion of nose piece 134. Female contact connector 130 also includes a radial
outer portion
58.
Sleeve 132 is generally cylindrical having a central passageway 60
therethrough. Sleeve
132 has an inner ertd 138 which opens adjacent recess 64 in casing 56 and
includes internal
threads 136. The other end of sleeve 132 includes an annular shoulder and
groove for latching
engagement with the mating annular groove and shoulder of nose piece 134. Nose
piece 134
forms an inwardly facing annular frusto-conical shoulder 142 which serves as a
stop shoulder
for contact assembly 140 as hereinafter described.
Female contact connector 130 further includes a contact assembly 140. Contact
assembly
14.0 includes a contact holder 1:50, a stationary female contact 160, a
sliding female contact 162,
an arc snuffer housing 164, and an arc snuffer 110. Contact assembly 140 is
disposed within
inmrnal passageway 60 of conductive sleeve 132. Contact holder 150, as
distinguished from
cylindrical contact holder 80 o~f the preferred embodiment, is a shaft-like
end plug having an
enlarged diameter end forming an inwardly facing annular shoulder 144. A
threaded bore 146
passes into the inner end of contact holder 150 for threading engagement to a
stud (not shown)
extending from the bushing well. A collar 152 is press fitted over the
enlarged diameter inner
end of holder 150 and includes a plurality of pressure relief holes 154.
External threads are
pr~wided around collar 152 for threaded engagement with threads 136 on sleeve
50. A snap ring
158 is received within a groove in the outer end of holder 150 to maintain
contact holder 150
within conductive sleeve 132. A hex slot 148 is provided in the outer end of
holder 150 to
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21 058 1 0
rE~eive a hexrod for threading collar 152 to sleeve 50. Threaded bore 146 and
hex slot 148 are
a:ntered on the central axis 8:5 of sleeve 132. The inwardly projecting
portion 151 of contact
holder 150 has an outer diarneter sized to be press fitted into the open
cylindrical end of
stationary female contact 160. Contact 160 is also staked to holder 150. The
inner terminal end
otf female contact 160 abuts armular shoulder 144 of holder 150.
Pressure relief holes 154 prevent the trapping of air in recess 64 between
female contact
connector 130 and the bushing well (not shown). As connector 130 is threaded
into the bushing
well, air is allowed to pass through relief holes 154 from recess 64. Trapped
air in recess 64
could hinder the assembly of contact connector 130 to the bushing well.
Female contact 160 includes a barrel portion 168 which receives projecting
portion 151
of contact holder 150, and a plurality of projecting contact fingers 94. The
barrel 168 is affixed
to contact holder 150 and therefore is stationary within conductive sleeve
132.
Sliding female contact 162 is generally cylindrical so as to be received over
the outer end
of stationary female contact 1E~0 having fingers 94. That portion of the outer
circumferential
surface of contact 160 engaging contact 162 is knurled to provide frictional
engagement. Sliding
female contact 162 is in electrical engagement with stationary female contact
160. Sliding
fernale contact 162 also includes a plurality of azimuthally spaced fingers
170 which are disposed
ext:eriorly of and adjacent to fingers 94 on stationary female contact 160 in
the normal,
contracted position of contact assembly 140 shown in Figure 10.
Tubular arc snuffer housing 164 is generally cylindrical and includes an
enlarged
diameter portion 172 which is sized to slidingly receive sliding female
contact 162 together with
the outer end of stationary female contact 160 having contact fingers 94. The
change in
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21 058 1 0
diameter of tubular sleeve 164 forms an inwardly facing frusto-conical
shoulder 174 which is
adjacent to the terminal ends of contact fingers 170 on sliding female contact
162. The outer
pbrtion 165 of arc snuffer housing 164 has the smaller diameter and is sized
to be slidingly
r~~:eived within nose piece 134. The inner surface is tapered slightly so as
to form a conical
Wrap 167. The arc-quenching;, gas-generating arc snuffer 110 hag a
correspondingly tapered
outer conical surface so as to conform with the interior conical wall 167 of
arc snuffer housing
164. Arc snuffer 110 includes a cylindrical inner bore i 11 for receiving
probe 40.
Referring now to Figures 10 and 11, sliding female contact 162 is activated on
fault close
only. As the male contact prone 40 approaches sliding female contact 162 and
stationary female
contact 160 and a short circuit condition exists, an arc is struck which
passes along the inner
circumferential surface 111 of arc snuffer 110 causing the generation of arc-
quenching gases
which a,re directed within the bore of stationary female contact 160. The
pressure of the gases
acts upon the arc snuffer assembly causing sliding female contact 162, arc
snuffer housing 164,
and arc snuffer 110 to move outward as shown in Figure 11 toward the opening
of bore 60 and
probe 40 to establish electrical contact between sliding female contacts 170
and male contact
probe 40.
Referring now to Figuna 12 and 13, there is shown another alternative
embodiment of
the; female contact connector of the present invention. This alternative
female contact connector
180 includes a conductive sleeve 190 having a non-conductive nose piece 192
secured to one end
of sleeve 190 by a latching means 54, and a casing 56 bonded to the outer
surface of sleeve 190
and a portion of nose piece 192. The conductive sleeve 190 is generally
cylindrical forming a
bore 196. Latching means 54 :includes corresponding annular grooves and
latching shoulders
23
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on the inner terminal end of nose piece i92 and outer terminal end of
conductive sleeve 190
which latch together to form means 54.
As shown in Figure 12, female contact connector 180 includes a contact
assembly 200.
Contact assembly 200 includes an integral contact holder/female contact 210, a
tubular arc
;snuffer housing 100, and an arc-quenching, gas-generating arc_ snuffer 110.
Contact
llolder/female contact 210 in<:ludes an inner contact holder end 220 having
external threads 202
lhreadingly engaging at 204 internal threads on the inner end of conductive
sleeve 190. Contact
holder end 220 includes a threaded bore 212 for threading engagement with a
stud (not shown)
extending from the bushing vvell.
The integral contact holder/female contact 210 includes a spiraled tubular
body 214
disposed within the straight walled cylindrical bore 196 of conductive sleeve
190. Tubular body
14 is spirally cut therearound at 216 to allow tubular body 214 to be extended
outwardly as
shown in Figure 13. The outer end 218 of contact holder/female contact 210
includes a plurality
of azimuthally spaced contact fingers 94. The arc snuffer housing 100 receives
contact fingers
94 and is mounted on outer end 218 by melting the plastic of housing 100
around an external
knurled surface circumscribing end 218. Arc snuffer 110 is molded within
plastic housing 100
between shoulder 114 and annular tang 222. The common walls of arc snuffer
housing 100 and
arc snuffer 110 are sonically ;shaped as shown.
Figure 12 illustrates the; normal contracted position of female contact
connector 180. The
spiral tubular body 214 of intE:gral contact holder/female contact 210 is in
its normal position.
As shown in Figure 13, during fault closure, the pressurized gas builds within
bore 196 to move
the arc snuffer assembly mounted on outer end 218 of contact holder/female
contact 210 to the
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21 058 1 0
outer outward, expanded position. As end 218 moves outward, spiral tubular
body 214 becomes
elongated as it extends to the outer position. The spiral cuts 216 around
tubular body 214 allow
body 214 to collapse and expend longitudinally as the spirals tighten thereby
allowing elongation.
Referring now to Figures 14 and 15, there is shown still another alternative
embodiment
of the female contact connector of the present invention. This embodiment of
the female contact
connector 250 includes a conductive sleeve 260 having a non-conductive nose
piece 52 secured
to one end of sleeve 260 by latching means 54, and a casing 56 surrounding and
bounded to the
outer surface of sleeve 260, <i portion of nose piece 52 and a portion of
contact holder 262,
hereinafter describe. The female contact connector 250 further includes a
female contact
a:~sembly 270 which includes the contact holder 262, a female contact 280, a
arc snuffer
housing 100 and an arc-quenching, gas-generating arc snuffer 110.
Sleeve 260 is generally cylindrical forming a central inner passageway 60
therethrough.
Contact assembly 270 is disposed within passageway 60 of conductive sleeve
260. Sleeve 260
includes an inwardly and rad:ially projecting annular shoulder 282 at its mid-
portion which
sl:idingly engages the external surface of female contact 280. The contact
holder 262 is inserts
into the inner terminal end 264 of sleeve 260 with end 264 mechanically formed
around contact
holder 262 to affix holder 262 within conductive sleeve 260. Contact holder
262 includes a
threads bore 266 for thread engagement with a stud (not shown) extending from
the bushing
well.
A neck 268 projects from the outer end of contact holder 262 into bore 60 of
conductive
sleeve 260. Neck 268 includes an enlarged diameter head 272 on its terminal
end forming an
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21 058 1 0
inwardly facing annular shoulder 274 and an outwardly facing conical shoulder
276. A hex slot
2',~8 extends into neck 268 for receiving a hexrod (not shown).
Female contact 280 includes a plurality of azimuthally spaced contact fingers
94 on its
outer end which is secured within the inner end of arc snuffer housing 100 by
heating contact
280 and melting housing 100. The inner end 284 of female contact 280 includes
a plurality of
inwardly directed mechanical flanges 286 and a plurality of outwardly directed
mechanical
flanges 288. The mechanical flanges 286, 288 are disposed orr longitudinal
arms cut in the
circumferential wall of female contact 280 with inwardly directed mechanical
flanges 286 having
a greater longitudinal length than outwardly directed mechanical flanges 288
thereby projecting
further from female contact 280. In the normal, contracted position as shown
in Figure 14, the
inwardly directed mechanical flanges 286 cam outward upon engagement of
conical shoulder 276
so as to become in abutting enl;agement with inwardly facing annular shoulder
274. Outwardly
e~;tending mechanical flanges 288 are adapted to engage annular shoulder 282
of conductive
sleeve 260 upon the outward movement of female contact assembly 270 as shown
in Figure 15.
Referring now to Figure 15, during fault closure, the arc-quenching gases are
directed
within the bore 60 shearing inwardly directed mechanical flanges 286 and onto
arc snuffer
assembly and causing the contact assembly 270 to travel outwardly as shown in
Figure 12 until
outwardly directed mechanical flanges 288 engage annular shoulder 282.
Referring now to Figures 16 and 17, there is shown a still another alternative
embodiment of the female contact connector of the present invention. This
alternative female
contact connector 290 includes a conductive sleeve 300 which is substantially
the same as sleeve
2150 of the embodiment with the exception that conductive sleeve 300 does not
include an
26
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21 058 1 0
iinwardly directed annular shoulder at its mid-point. Conductive sleeve 300
includes a non-
~;onductive nose piece 52 attached to one end by latching means 194 and its
other end is attached
~:o end plug 310 in a manner identical to that of the alternative embodiment
shown in Figures
14 and 15. The female contact connector 290 further includes a contact
assembly 320. Contact
assembly 320 includes a contact holder 310, a female contact 322, a arc
snuffer 100, and an arc-
quenching, gas-generating guide tube 110. The contact assembly 320 is disposed
within internal
passageway 60 of conductive sleeve 300.
Contact holder 310 includes a threaded bore 266 and a neck 312 projecting into
the bore
fi0 of conductive sleeve 200 like that of the embodiment shown in Figures 14
and 15. Neck 312
includes an outer annular shoulder 314, substantially the same as annular head
272 shown in
Figures 14 and 15, and also includes an inner annular head 316 located around
the medial
Fbrtion of neck 312. Each of the annular heads 314, 316 include an outwardly
facing conical
shoulder and an inwardly facing abutting shoulder.
Female contact 322 includes a plurality of azimuthally spaced contact fingers
94 on its
outer end which is secured within one end of arc snuffer 100. Female contact
322 further
includes a plurality of tangs 324 projecting radially outward around its mid-
portion for
engagement with the inner terminal end 101 of arc snuffer 100. The inner end
302 of female
c~~ntact 322 includes a plurality of arms 304 formed by longitudinal slots in
the walls of female
contact 322. Each arm 304 includes a radially projecting raised portion 306
which engages the
interior circumferential wall of conductive sleeve 300. Adjacent the terminal
end of arms 304,
there is stamped an inwardly projecting tang 308 adapted for engagement with
annular heads 314
a~ld 316 of contact holder 310.
27
21058 1 0
Referring now to Figures 16 and 17, the inwardly directed tangs 308 engage the
inner
a~~nular head 316 on neck 312 of contact holder 310 in the normal, contracted
position. Upon
fault closure, the arc-quenching gases are directed within the bore 60
expanding arms 304 and
causing the tangs 308 to disengage annular head 316. Tangs 308 then become
engaged with
a~~nular head 314 to limit the outward movement of contact assembly 320.
Referring now to Figure 18, there is an alternative to the embodiment shown in
Figures
16 and 17. In this alternative, modifications have been made to the conductive
sleeve and
a~ntact holder to allow assembly after the rubber components, such as the
casing, have already
b,~n molded. In all previous embodiments, the elastomeric, insulating casing
56 has been
b~mded to the outer surface of the conductive sleeve and a portion of the nose
piece after the
assembly of the sleeve and nose piece. As shown in Figure 18, the female
contact connector
340 includes an elastomeric iinsulating casing 342 having a generally
cylindrical bore 344
therethrough and a reduced diameter portion 346 which forms a neck with a bore
348
therethrough. Bore 348 opens into recess 64 to receive a portion of the
bushing well (not
shown). A threaded collar 35:Z is molded and bonded within the portion 346
such that threads
3-'.4 interiorly of the collar 352 are adapted for threaded engagement with
the inner end of
ccmductive sleeve 350 as hereinafter described. Collar 352 centers sleeve 350.
The non-
conductive nose piece 356 is also molded and bonded to casing 342 and includes
a neck down
portion 358 which is received by a counterbore 362 in the outer terminal end
of casing 342.
Non-conductive nose piece 356 is not connected to conductive sleeve 350 during
the molding
of casing 342.
28
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21 058 1 0
Conductive sleeve 3~0 is generally cylindrical having external threads for
threaded
f;ngagement with nose piece 356 and a reduced diameter portion 368 at its
inner end having
external threads 370 adapted for threaded engagement with the internal threads
354 of collar
352.
The contact holder 360 includes a rod-like body having a neck 372 with annular
heads
?'~74, 376 projecting into the >rxe 378 of conductive sleeve 350. A tapped
bore 380 extends into
dhe inner end of holder 360 for receiving a stud (not shown) extending from
the bushing well.
The neck 346 of sleeve 342 and the inner end of holder 360 have aligned snap
ring grooves for
rmeiving a snap ring 382 to secure holder 360 within neck 346 and thus casing
342. The female
contact assembly 320 shown in Figure 16 may be used with this alternative
embodiment.
Referring now to Figures 19-23, there is shown still another alternative
embodiment of
ttie female contact connector o:F the present invention. This embodiment of
the female connector
400 includes an integral bushing nose/conductive sleeve 410 made of a non-
conductive material.
A. casing 402 of elastomeric insulating material surrounds and is bonded to
the outer surface of
nose piece/conductive sleeve 4.10 and a portion of contact holder 420 as
hereinafter described.
The nose 412 includes a circumferential external groove 414 which serves as a
securing detente
for complimentary rib portion 33 associated with the elastomeric housing 32 of
male contact
connector 30. The bushing nose/conductive sleeve 410 includes a reduced outer
diameter
cylindrical body 417 forming an inwardly facing annular shoulder 416. The
cylindrical body
417 includes an enlarged inner diameter counterbore 418 at its inner end for
receiving the outer
end of contact holder 420 as hereinafter described. The interior and exterior
of the counterbore
418 is coated with a semi-conductive material making electrical contact with
the outer end of
29
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21 05~ 1 0
contact holder 420. The inner cylindrical wall 438 of nose piece/conductive
piece 410 includes
a pair of J-slots 422 for receiving arc snuffer housing 450 as hereinafter
described.
The female contact connector 400 further includes a contact assembly 430.
Contact
.assembly 430 includes a contact holder 420, a female contact 440, a arc
snuffer housing 450,
;ind an arc-quenching, gas-generating arc snuffer 110. Contact assembly 430 is
disposed_ within
she casing 402 and nose pieaJconductive sleeve 410. .
Contact holder 420 is generally cylindrical having a central passageway 60
therethrough.
l3older 420 has a tapered inner end 424. Tapere inner end 424 includes a
threaded bore 426
open to recess 64 to receive a portion of the bushing well (not shown). A hex
slot 428 is
yrovided to receive a hexrod for turning the assembly to threadingly engage a
stud (not shown)
extending from the bushing vvell. The open end of contact holder 420 is
receive within the
enlarged diameter end 418 of nose piece/sleeve 410.
The female contact 4~10 is generally cylindrical and includes a barrel 432
having a
plurality of projecting contact fingers 94 extending from its outer end.
Female contact fingers
94 are forma by a plurality o:f slots 96 around barrel 432. The inner end of
female contact 440
i<.~ knurled at 98 around its outer surface to provide a biting and frictional
engagement with the
inner circumferential wall 434 of contact holder 420. The knurled surface 98
ensures good
electrical contact between contact holder 420 and female contact 440 and also
inhibits the
rexiprocation of female contact 440 within the bore 421 of contact holder 420.
The female
a>ntact 440 is also knurled at 436 for disposal within arc snuffer housing
450.
The fault close stopping mechanism is a twist lock design incorporated into
the nose
piece/conductive sleeve 410 and arc snuffer housing 450. As best shown in
Figure 21, the J-
4
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21 050 1 0
slots 422 in the internal wall 438 of nose piece/conductive sleeve 410 each
include a longitudinal
portion 442 and a transver~~e portion 444. The longitudinal portion 442
extends from the
terminal end at nose bushing 412 to counterbore 418. Transverse portion 444 is
adjacent
counterbore 418. Arc snuffer housing 450 includes a pair of transverse keys
452 at its inner end
454 and a pair of longitudinal keys 456 at its outer erg 45~ As best shown in
Figures 22 and
23, upon assembly, each transverse key 452 is aligned with the longitudinal
portion 442 of a J-
slot 422. Upon transverse ~;ey 452 entering the transverse portion 444 of J-
slot 422, the arc
snuffer housing 450 is twisted or rotated to move transverse key 452 into
transverse portion 444
~~f J-slot 422 and thus align longitudinal key 456 with the longitudinal
portion 442 of J-slot 422.
'The arc snuffer housing 450 is then further inserted into nose
piece/conductive sleeve 410 with
ilongitudinal key 456 being rexeived by longitudinal portion 442 of J-slot
422. In this manner,
~~rc snuffer housing 450 is incorporated into nose piece/conductive sleeve
410. Transverse key
~t52 has a longitudinal dimension substantially smaller than the longitudinal
dimension of the
transverse portion 444 of J-slot 422 thereby providing a clearance 462 best
shown in Figure 22.
'Chis clearance 462 allows arc; snuffer housing 450 as a part of contact
assembly 430, to move
longitudinally within nose pieee/conductive sleeve 410 during fault closure.
Referring now to Figure 20, during fault closure, the arc-quenching gases are
directed
within the bore 421 applying a~ force to the terminal end of female contact
440 so as to overcome
the frictional engagement of knurl surface 98 thereby causing the contact
assembly 440 to travel
outwardly as shown in Figure. 20 until reaching the fault closure stopping
mechanism.
31
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21 058 1 0
While a preferred embodiment of the invention has been shown and described,
modifications thereof can be made by one skilled in the art without departing
from the spirit of
the invention.
32
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